Control device, control method for water heater, and program

ABSTRACT

In a control device, an instruction acquirer acquires an instruction to suppress in a specified period supplying of generated power generated by power generator installed in a power-consuming area to a commercial electrical power system. Upon the instruction acquirer acquiring the instruction, a water heater controller commands a water heater installed in the power-consuming area to perform a water heat-up operation when a predetermined condition is satisfied in the specified period.

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage application of InternationalPatent Application No. PCT/JP2015/086274 filed on Dec. 25, 2015, thedisclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a control device, a control method fora water heater, and a program.

BACKGROUND ART

Technology using natural energy as typified by photovoltaic energy andwind energy is attracting attention in recent years, and with increasingfrequency, the power consumer owns a power generator that generatespower from the natural energy. Such a power consumer can consume thepower generated by the power generator, and can supply excess power tothe commercial electrical power system and sell the excess power to anelectric utility operator. Thus the power consumer can decrease thepower purchased from the commercial electrical power system and canobtain an economic benefit.

However, a supply-demand imbalance may occur in the commercialelectrical power system due to the reverse flow supplying power back tothe commercial electrical power system from the power generator of thepower consumer. For example, when the weather is clear on a non-workday,the demand for power from the commercial electrical power systemdecreases, and also the power supplied to the commercial electricalpower system from the power generator of the power consumer increases.

Thus in order to maintain the supply-demand balance of the commercialelectrical power system, electric utility operators are promoting themaintaining of a system for prior designation of time periods to thepower consumer for suppressing the reverse flow of power. For example,the Agency for Natural Resources and Energy of Japan in 2014 announcedrules for control of the output from photovoltaic power generation.These output control rules are for adjusting the output of powergenerated by a power generator, thereby suppressing the sale of powerfrom the power consumer to the commercial electrical power system.

Further, technology is proposed for consuming the generated power asmuch as possible by the power consumer and decreasing the sale of thegenerated power to the commercial electrical power system. For example,Patent Literature 1 discloses technology for predicting a time periodwhen much reverse flow of power is generated, and in the forecast timeperiod, causing operation of a heat pump-type water heater deviceequipped with a hot water storage tank. Power consumption by the waterheater equipped with the hot water storage tank is generally high, andthus the technology disclosed in Patent Literature 1 can effectivelydecrease the reverse flow of power.

CITATION LIST Patent Literature

Patent Literature 1: International Publication No. WO 2012/090365

SUMMARY OF INVENTION Technical Problem

However, the technology disclosed in Patent Literature 1 does not, inthe aforementioned manner, decrease the reverse flow of power inresponse to an instruction to suppress the reverse flow of power. In theperiod designated for suppressing the reverse flow of power, a powergeneration loss occurs due to the suppression of output of powergenerated by the power generator. Thus there is demand for increasingutilization efficiency of power and decreasing the power generation lossoccurring in the period designated for suppression of the reverse flowof power.

In order to solve the above described problem, an object of the presentdisclosure is to provide a control device and the like capable ofcausing an improvement of the utilization efficiency of power.

Solution to Problem

In order to attain the aforementioned objective, the control deviceaccording to the present disclosure includes:

instruction acquiring means for acquiring an instruction to suppress ina specified period supplying of a generated power generated by a powergenerator installed in a power-consuming area to a commercial electricalpower system; and

water heater control means for, upon the instruction acquiring meansacquiring the instruction, commanding a water heater installed in thepower-consuming area to perform a water heat-up operation when apredetermined condition is satisfied in the specified period.

Advantageous Effects of Invention

According to the present disclosure, in the case in which theinstruction to suppress in the specified period supplying of generatedpower generated by the power generator installed in the power-consumingarea to the commercial electrical power system is acquired, when apredetermined condition is satisfied in the specified period, the waterheater installed in the power-consuming area is commanded to perform thewater heat-up operation. Thus the present disclosure enables animprovement in the utilization efficiency of power.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an overall configuration of an energymanagement system according to an embodiment of the present disclosure;

FIG. 2 is a chart and table for description of a suppression instructiondistributed by a power server;

FIG. 3 is a chart illustrating trends in output power from a powergenerator during suppression of photovoltaic power;

FIG. 4 is a block diagram illustrating a hardware configuration of acontrol device;

FIG. 5 is a block diagram illustrating a functional configuration of thecontrol device;

FIG. 6 is a drawing illustrating an example of a setting screendisplayed by an operating terminal;

FIG. 7 is a table illustrating an example of a power database;

FIG. 8 is a chart illustrating a relationship between generated powerand consumed power during suppression of PV power, and illustratingtiming of a water heat-up operation to be performed by a water heater;

FIG. 9 is a chart illustrating transitioning in measured values of anoutput power amount from the power generator occurring in a three dayperiod prior to a day of execution of the suppression of PV power;

FIG. 10 is a chart illustrating trends in maximum values among themeasured values of the output power amount from the power generatoroccurring in the three day period prior to the day of execution of thesuppression of PV power;

FIG. 11 is a diagram illustrating an example of a display screendisplayed by the operating terminal during PV power suppression.

FIG. 12 is a sequence diagram illustrating a summary of processingexecuted by the energy management system;

FIG. 13 is a flow chart illustrating an example of PV-PCS outputsuppression processing;

FIG. 14 is a flow chart illustrating an example of PV suppressiondetermination processing executed by the control device;

FIG. 15 is a diagram illustrating two thresholds used in the conditionsfor commanding the water heater to perform the water heat-up operation;and

FIG. 16 is a block diagram illustrating an overall configuration of anenergy management system according to a modified example.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are described below in detail withreference to drawings. In the drawings, components that are the same orequivalent are assigned the same reference signs.

FIG. 1 illustrates an overall configuration of an energy managementsystem 1 according to an embodiment of the present disclosure. Theenergy management system 1 is a system termed a home energy managementsystem (HEMS) that performs management of power used in a generalhousehold. The energy management system 1 includes a control device 2,an operating terminal 3, a power measurement device 4, a water heater 5,and a power generator 6. Further, the control device 2 is connected to apower server 14 and a data server 13 via a wide area network N.

The control device 2 is arranged at a suitable location within a home H,which is a power-consuming area for consumption of power, monitors powerconsumed in the home H, and displays a power consumption state via theoperating terminal 3. Further, the control device 2 controls operationof the water heater 5 and multiple apparatuses 7 (apparatuses 7-1, 7-2,and the like), and monitors operational states of these components. Thecontrol device 2 is described in detail hereinafter.

The operating terminal 3 (user interface device) is a portable apparatussuch as a smartphone, tablet terminal, remote controller, portablephone, or notebook-type personal computer, for example. The operatingterminal 3 includes an input device such as a touch panel, touch pad, orpush button, a display device such as an organic electro-luminescence(EL) display or a liquid crystal display, and a communication interface.The operating terminal 3 performs communication with the control device2 according to a widely known communication protocol such as Wi-Fi(registered trademark), Wi-SUN (registered trademark), a wired localarea network (LAN), or the like. The operating terminal 3 receives anoperation from a user, and transmits to the control device 2 informationindicating content of the received operation. Further, the operatingterminal 3 receives from the control device 2 information to bepresented to the user, and displays the received information. In thismanner, the operating terminal 3 serves as an interface (user interface)with the user.

The power measurement device 4 measures values of power sent to each ofpower lines D1 to D3 arranged in the home H. The power line D1 isarranged between a commercial electrical power system 8 and a powerdistribution panel 9, the power line D2 is arranged between the powergenerator 6 and the power distribution panel 9, and the power line D3 isarranged between the power distribution panel 9 and the water heater 5.The power measurement device 4 is connected through communication linesto a CT1 (CT means “current transformer” hereinafter) connected to thepower line D1, a CT2 connected to the power line D2, and a CT3 connectedto the power line D3. CT1 to CT3 are sensors that measure alternatingcurrent.

The CT1 installed at the power line D1 measures a power Pb supplied fromthe commercial electrical power system 8 to the home H. This power Pbcorresponds to power (purchased power) purchased from the electricutility operator by the power consumer that consumes power in the homeH. The CT2 installed at the power line D2 measures a power Pg output tothe power distribution panel 9 from the power generator 6. This power Pgis power generated by the power generator 6 and corresponds to powersupplied within the home H and capable of use within the home H. The CT3installed at the power line D3 measures a power Pe supplied to the waterheater 5 from the distribution panel 9. This power Pe corresponds topower consumed by the water heater 5.

Further, if no power storage equipment such as a stationary type storagebattery or an electric vehicle is arranged, a sum of the power Pbmeasured by the CT1 and the power Pg measured by the CT2 corresponds tototal consumed power of the home H that is the power-consuming area.That is to say, the following relationship is established for the totalconsumed power of the home H: Pc=Pb+Pg. Further, the expression “totalconsumed power of the home H” is taken to include power consumed withinthe grounds of the home H. Hereinafter, the total consumed power issometimes referred to simply as “consumed power”.

When the power Pg output from the power generator 6 exceeds the totalconsumed power Pc of the home H, excess power occurs at the home H. Whenexcess power occurs, the power consumer of the home H can sell power tothe electric utility operator by supplying the excess power to thecommercial electrical power system 8 as reverse flow power. The powerreturned to the electric utility operator from the power consumer by thesupply of power from the home H to the commercial electrical powersystem 8 is referred to as the “reverse flow power”. During the periodof occurrence of the reverse flow power, the power Pb of the power lineD1 measured by CT1 is a negative value.

The power measurement device 4 includes non-illustrated components suchas a CPU, a ROM, a RAM, a communication interface, read-writeablenon-volatile semiconductor memory, and the like. Further, the powermeasurement device 4 includes a wireless communication interface andcommunicates with the control device 2 via a wireless network installedin the home H. The wireless network is a network standardized on theEnergy Conservation and Homecare Network Lite (ECHONET Lite), forexample. Further, the power measurement device 4 may be configured toconnect to this wireless network through a non-illustrated externalcommunication adapter.

In response to the request from the control device 2, the powermeasurement device 4 generates measurement data containing, asmeasurement values, power sent through the power lines D1 to D3 andobtained by measurement, and transmits the generated measurement data tothe control device 2. Equipment unit addresses of the power measurementdevice 4, IDs of the power lines, measurement times, and the like arecontained in the transmitted measurement data. Further, in response tothe request from the control device 2, the power measurement device 4may generate, and then transmit to the control device 2, measurementdata that collectively contains each of the measurement values of thepower lines D1 to D3.

The apparatus 7 (apparatuses 7-1, 7-2, and the like) is an electricalapparatus such as an air conditioner, lighting appliance, floor heatingsystem, refrigerator, induction heating (IH) cooker, or television, forexample. The apparatuses 7-1, 7-2, and the like are arranged within thehome H (including the grounds thereof), and are electrically connectedto the commercial electrical power system 8 and the power generator 6via the power lines D4, D5, and the like branching from the powerdistribution panel 9.

Each of the apparatuses 7 includes a wireless communication interfaceand communicates with the control device 2 via the aforementionedwireless network installed in the home H. Further, each of theapparatuses 7 may be configured to connect with the wireless network viaa non-illustrated external communication adapter. In response to arequest from the control device 2, each of the apparatuses 7 sends tothe control device 2, via the wireless network, data (operational statedata) containing information indicating an equipment identification(ID), a present time, and an operational state.

The water heater 5 is a hot water storage-type water heater including aheat pump unit 50 and a tank unit 51. The heat pump unit 50 and the tankunit 51 are interconnected by piping 52 through which hot water flows.The water heater 5 is electrically connected to the commercialelectrical power system 8 and the power generator 6 via the power lineD3 branching from the power distribution panel 9. The water heater 5 isdescribed hereinafter.

Heat Pump Unit 50

The heat pump unit 50 of the water heater 5 includes non-illustratedcomponents such as a compressor, a first heat exchanger, an expansionvalve, a second heat exchanger, an air fan, and a control board. Thecompressor, the first heat exchanger, the expansion valve, and thesecond heat exchanger are connected in a loop to a cooling cycle circuitfor circulation of a refrigerant. The cooling cycle circuit is alsotermed the “refrigerant circuit”.

The compressor compresses the refrigerant and causes increases intemperature and pressure. The compressor includes an inverter circuitthat can change a capacity (output amount per unit) in response to adrive frequency. The compressor changes the aforementioned capacity inaccordance with an instruction from the control board.

The first heat exchanger is a heat source for heating to raise atemperature of municipal tap water up to a target heat-up temperature.The heat-up temperature is also referred to as the “hot water storagetemperature”. The first heat exchanger is a heat exchanger such as aplate type heat exchanger or a double-tube type heat exchanger, andperforms the exchange of heat between the refrigerant and water, thatis, low temperature water. Heat exchange at the first heat exchangerreleases heat of the refrigerant, and causes the water to absorb heatand rise in temperature.

The expansion valve allows expansion of the refrigerant and causes alowering of temperature and pressure. Degree of opening of the expansionvalve changes in accordance with an instruction from the control board.

The second heat exchanger performs heat exchange between the refrigerantand exterior air blown by the fan. Due to the heat exchange by thesecond heat exchanger, heat absorbed by the refrigerant is released tothe exterior air, and the temperature decreases.

The control board includes components such as a central processing unit(CPU throughout), a read only memory (ROM throughout), a random accessmemory (RAM throughout), a communication interface, and a read-writablenon-volatile semiconductor memory. The control board is connected in acommunication-capable manner via respective communication lines with thecompressor, the expansion valve, and the fan, and the control boardcontrols operation of these components. Further, the control board isconnected in a communication-capable manner via non-illustratedcommunication lines with a below-described hot water supply controller54 of the tank unit 51.

Tank Unit 51

The tank unit 51 includes the hot water storage tank 53, the hot watersupply controller 54, a mixing valve 56, and the like. These componentsare contained within a metallic external case.

The hot water storage tank 53 is formed from a metal such as stainlesssteel or from a resin. Non-illustrated thermal insulation is arranged atthe exterior of the hot water storage tank 53. Thus the high temperaturehot water (referred to hereinafter as the high temperature water) withinthe hot water storage tank 53 can be maintained at temperature for along time period.

The hot water supply controller 54 includes non-illustrated componentssuch as a CPU, a ROM, a RAM, a communication interface, and aread-writable non-volatile semiconductor memory, and provides overallcontrol of the water heater 5. The hot water supply controller 54 isconnected in a communication-capable manner via a non-illustratedcommunication line with the control board of the heat pump unit 50.Further, the hot water supply controller 54 is connected in acommunication-capable manner via the communication line 59 with a remotecontroller 55. Further, the hot water supply controller 54 is connectedwith the control device 2 in a communication-capable manner via theaforementioned wireless network installed in the home H.

Remote Controller 55

The remote controller 55 is a terminal device for displaying andproviding to the user information such as an operational state and a hotwater storage state of the water heater 5. The remote controller 55 isarranged in a bathtub-equipped room in the home H and receives from theuser an operational input relating to heating up, hot water supply, orthe like.

The remote controller 55 includes non-illustrated components such as aCPU, a ROM, a RAM, a read-writable non-volatile semiconductor memory, aninput device such as a push button, a touch panel, or a touch pad, adisplay device such as an organic EL display or a liquid crystaldisplay, and a communication interface, and the like.

Water Heat-Up Operation

At the start time of the water heat-up operation, the high temperaturewater within the hot water storage tank 53 is consumed, and themunicipal tap water at a temperature close to that of low temperaturewater is retained in the bottom portion of the hot water storage tank53. By operation of a non-illustrated pump, the low temperature waterenters the first heat exchanger of the heat pump unit 50, the water israised in temperature by exchange of heat with the refrigerant, and thewater becomes high temperature water. This high temperature water isreturned to the upper portion of the hot water storage tank 53, andwithin the hot water storage tank 53, the high temperature water in theupper portion thereof and the low temperature water remaining in thelower portion form temperature layers, and a temperature interface layeris formed between the high temperature water and the low temperaturewater.

When the heating up amount increases and the region of the hightemperature water becomes large, the temperature interface layerapproaches the bottom portion of the hot water storage tank 53, and thetemperature (inlet water temperature) of the water entering the firstheat exchanger gradually rises.

Hot Water Supply Operation

A hot water output pipe is connected to the upper portion of the hotwater storage tank 53, and high temperature water discharged via the hotwater output pipe from the hot water storage tank 53 is mixed with themunicipal tap water by the mixing valve 56. Thus the resultant hot waterhas the temperature, such as 40° C., desired by the user, and issupplied to a hot water supply terminal such as a shower 57 or a faucet58 installed in a bathtub-equipped room, for example. At this time,volume of the high temperature water discharged from the upper portionof the hot water storage tank 53 is equal to the volume of municipal tapwater supplied by water pipe pressure from a non-illustrated watersupply pipe connected to the bottom of the hot water storage tank 53.Thus the temperature interface layer within the hot water storage tank53 moves upward. When the amount of the high temperature water becomeslow, the water heater 5 performs additional heating up.

The power generator 6 is described next. The power generator 6 isinstalled at the home H and is equipment that generates electricity fromsunlight, which is a natural energy source. Although the commercialelectrical power system 8 supplies power to an undefined plurality ofpower-consuming areas including the home H, the power generator 6 isowned by a power consumer of a specific power-consuming area, and isarranged to supply power to the home H that is the specificpower-consuming area. This type of power generator 6 is also referred toas a distributed-type power source.

The power generator 6 includes a photovoltaic (abbreviated throughout as“PV”) panel 10 for PV power generation and a PV-power conditioningsystem (abbreviated throughout as “PCS”) 11. The PV panel 10 is a solarpanel such as a polycrystalline type solar panel, for example. The PVpanel 10 is arranged upon a roof of the home H and generatesphotovoltaic power by conversion of solar energy into electrical energy.

The PV-PCS 11 receives the supplied power generated by the PV panel 10and outputs the supplied power via the power line D2 to the powerdistribution panel 9. At this time, the PV-PCS 11 converts the powersupplied from the PV panel 10 by converting and outputting at aprescribed conversion efficiency from direct-current power toalternating-current power so that the supplied power can be used withinthe home H.

The PV-PCS 11 includes non-illustrated components such as a CPU, a ROM,a RAM, a communication interface, and a read-writable non-volatilesemiconductor memory. Further, the PV-PCS 11 communicates with thecontrol device 2 via the aforementioned wireless network installed inthe home H. Further, the PV-PCS 11 may be configured to connect with thewireless network via a non-illustrated external adapter. The PV-PCS 11acquires from the control device 2 via the wireless network informationsuch as PV suppression instructions and measurement values of the powerPb, Pg, and Pe transmitted through the power lines D1 to D3,respectively, and measured by the power measurement device 4.

A router 12 is a device capable of communication with the data server 13and the power server 14 via the wide area network N, and is a broadbandrouter, for example. The control device 2 communicates with the dataserver 13 and the power server 14 via the router 12.

The data server 13 is a server for allowing the energy management system1 to function in cooperation with the control device 2, and is a serverthat provides resources such as cloud computing. The data server 13stores data required for the operation of the control device 2. The dataserver 13 acquires and accumulates via the control device 2 informationsuch as results of measurements by the power measurement device 4,operational states of the water heater 5 and the apparatuses 7 collectedby the control device 2, and power consumed under the operational state,for example. Further, the data server 13 stores, time slot-by-time slot,a purchased-power unit price for power from the commercial electricalpower system 8 and a sold-power unit price for the reverse flow power tothe commercial electrical power system 8. Further, the data server 13supplies data to the control device 2 in response to a request from thecontrol device 2.

The power server 14 is a server operated by the electric utilityoperator who provides a commercial power supply to each of the powerconsumers via the commercial electrical power system 8. The power server14 is connected in a communication-capable manner via the wide areanetwork N with the control device 2 arranged in the power-consumptionarea of each of the power consumers.

Upon satisfaction of a predetermined condition, the power server 14, toeach of the power consumers owning the power generator 6, distributes aninstruction to suppress the supply of power to the commercial electricalpower system 8 from the power generator 6 of the power consumer in thespecified period, that is to say, distributes an instruction to suppressthe reverse flow power. The reverse flow power is suppressed in thismanner to prevent a supply-demand imbalance in the commercial electricalpower system 8 due to an excess supply of power from the power consumersto the commercial electrical power system 8. The instruction distributedby the power server 14 to suppress the reverse flow power is referred tohereinafter as the “suppression instruction”, and controlling the outputof the power generator 6 to suppress the reverse flow power is referredto hereinafter as “PV suppression”. PV suppression is also termed“output suppression”, “output control”, or the like.

That is to say, specifically the power server 14 acquires from ameteorological organization meteorological information such as weatherinformation, solar insolation, sunlight hours, and the like for thelocation where the power generator 6 of each power consumer isinstalled, and creates a schedule for the PV suppression. Then by theday prior to execution of the PV suppression, the power server 14, inaccordance with the created schedule, delivers the suppressioninstruction to each power consumer. The execution period of the PVsuppression is the period when the generated power from the powergenerator 6 becomes excessive with respect to the supply-demand state ofthe commercial electrical power system 8, and for example, this periodis normally in a time slot when the weather is clear and a large amountof solar insolation is anticipated. Further, the power server 14 doesnot deliver the suppression instruction with respect to a day for whichthere is no requirement for the execution of PV suppression.

The suppression instruction distributed by the power server 14 includes:time information indicating a specified period for execution of the PVsuppression, and instruction value information indicating an instructionvalue of an output limit during suppression of the PV power of the powergenerator 6. That is to say, specifically the suppression instructiondesignates information that is a specified time slot occurring on aspecified day as the specified period for execution of the PVsuppression, that is to say, the year, month, day, and times of day(start time and end time) for execution of the PV suppression.

The suppression instruction designates, as the instruction value of theoutput limit of the power generator 6 during suppression of the PVpower, a fraction (%) of the power output to the power distributionpanel 9 of the home H from the PV-PCS 11 of the power generator 6relative to the rated power of the power generator 6. Here, the term“rated power” of the power generator 6 means the safe maximum powerpossible under appropriate conditions for the power generator 6, andthis specifically corresponds to the smaller capacity of the ratedcapacity of the PV panel 10 and the rated capacity of the PV-PCS 11.

FIG. 2 illustrates a specific example of the suppression instructiondistributed by the power server 14. The solid-line plot La within FIG. 2indicates the transitioning of generated power from the power generator6 occurring in the case in which there is no prior instruction for thePV suppression, and this plot indicates a value that is large during thedaytime and peaks at noon when solar insolation is high. In contrast,the dashed-line plot Lp within FIG. 2 indicates the transitioning of theinstruction value of the output limit of the power generator 6 asdesignated on the basis of the suppression instruction.

In the example of FIG. 2 , in time slots from 09:00 to 11:00 and from13:00 to 15:00 (times in the present disclosure indicated in 24-hourformat), suppression of the power output from the power generator 6 to40% of the rated power (for example, 2.0 kW relative to a rated power of5.0 kW) is designated. Further, in the time slot from 11:00 to 13:00,suppression of the power output from the power generator 6 to 0% of therated power of the power generator 6 is designated, that is to say, thedesignation is to output none of the power generated by the powergenerator 6. That is to say, in the time slot from 09:00 to 15:00 whenthe instruction value is less than 100%, the power output from the powergenerator 6 is suppressed. In contrast, in the time slots from 00:00 to09:00 and from 15:00 to 24:00 when the instruction value is 100%, thereis effectively no suppression of the power output from the powergenerator 6.

The suppression instruction designates the schedule of the PVsuppression in 30 minute increment units, for example, and designatesthe instruction value for the output of the power generator 6 inincrements of 1%, for example. Further, the suppression instruction maydesignate power units, such as kW units, rather than the fractionrelative to the rated power of the power generator 6. For example, inthe case in which the instruction value of 40% corresponds to the 2.0 kWoutput power and the limit value of 0% corresponds to 0 kW output poweras illustrated in FIG. 2 , the instruction values of the output powerfrom the power generator 6 may be designated as 2.0 kW and 0 kW.

Hereinafter, the value indicating the instruction value by the units ofpower is referred to as the “limit value”. In the case in which theinstruction value designates the fraction, the limit value correspondsto the value obtained by multiplying the instruction value times therated power of the power generator 6, and corresponds to the instructionvalue itself in the case in which the instruction value designatespower. Further, the limit value can be indicated in Wh increments of thepower amount by multiplying the limit value by time. For example, thevalue indicated in power amount units by multiplying the limit value bya 30 minute period, which is the increment of the schedule of the PVsuppression, is termed the “limit amount”, “suppression amount”, or thelike.

The control device 2 acquires the suppression instruction distributed bythe power server 14, and forwards the acquired suppression instructionto the PV-PCS 11 of the power generator 6. Upon acquiring thesuppression instruction forwarded from the control device 2, in theexecution period of the PV suppression designated via the suppressioninstruction, the PV-PCS 11 adjusts the output power such that thefraction of the output power from the power generator 6 relative to therated value of the power generator 6 does not exceed the instructedlimit value. The PV-PCS executes phase-advance phase control as themethod for the adjustment of the output power. Specifically, in theexecution period of the PV suppression, the PV-PCS 11 causes a reductionin effective power output from the PV-PCS 11 by offsetting the phase ofvoltage from the phase of current.

FIG. 3 illustrates transitioning of the output power from the powergenerator 6 during the suppressing of the PV power. The dot-dashed-lineplot Lc indicates transitioning of the total consumed power of the homeH and indicates high values from the afternoon to evening during which aconsumed power amount in a household generally increases. In contrast,the bold solid-line plot Lg in FIG. 3 indicates the output power fromthe power generator 6 within the power generated by the power generator6, that is to say, indicates transitioning of the power Pg measured bythe CT2.

In periods P1 and P4 when the PV suppression is not executed in theexample illustrated in FIG. 3 , the PV-PCS 11 does not suppress theoutput from the power generator 6. Thus the output power Pg from thepower generator 6 indicated by the bold solid-line plot Lg becomesequivalent to the generated power capable of being output by the powergenerator 6 as indicated by the thin solid-line plot La. This generatedpower capable of being output by the power generator 6 is the powerobtained by multiplying the conversion efficiency of the PV-PCS 11 bythe power generated by the PV panel 10 (panel generated power). Thegenerated power capable of being output by the power generator 6 isindicated hereinafter as Pa, and this is distinguished from the power Pgactually output from the power generator 6. The generated power Pacapable of being output by the power generator 6 is also referred to asthe “generated power Pa from the power generator 6”, the “generatedpower Pa”, or the like.

In contrast, in periods P2 and P3 when the PV suppression is executed,the PV-PCS 11 suppresses the output from the power generator 6. Thus theoutput power Pg from the power generator 6 indicated by the boldsolid-line plot Lg becomes smaller than the generated power Pa from thepower generator 6 indicated by the thin solid-line plot La.

More specifically, among the periods P2 and P3 when the PV suppressionis executed, the total consumed power Pc of the home H indicated by thedot-dashed-line plot Lc in the period P2 is smaller than the power (2.0kW) corresponding to the limit value indicated by the dashed-line plotLp. In this case, the PV-PCS 11 suppresses the output power Pg from thepower generator 6, as indicated by the bold solid-line plot Lg, down topower corresponding to the limit value.

In contrast, among the periods P2 and P3 when the PV suppression isexecuted, the total consumed power Pc of the home H indicated by thedot-dashed-line plot Lc in the period P3 is larger than the power (2.0kW) corresponding to the limit value indicated by the dashed-line plotLp. In this case, the PV-PCS 11 suppresses the output power Pg from thepower generator 6 as indicated by the bold solid-line plot Lg powermerely equivalent to the total consumed power Pc, rather than down tothe power corresponding to the limit value. However, in the period inwhich the generated power Pa capable of output from the power generationdevice 30 is less than the total consumed power Pc, such as the periodimmediately prior to 15:00 in FIG. 3 , for example, the PV-PCS 11 makesthe output power Pg from the power generator 6 equal to the generatedpower Pa capable of being output by the generated power.

The lower portion of FIG. 3 illustrates a relationship, at a time T1included in the period P2 and at a time T2 included in the period P3,between lost power and the generated power Pa capable of output from thepower generator 6. Here, the expression “lost power” indicates the powergeneration loss and is the power (Pa minus Pg) that is not output fromthe PV-PCS 11 despite generation of electricity by the PV panel 10 ofthe power generator 6. At the time T1 included in the period P2, theoutput power Pg from the power generator 6 is suppressed to the powercorresponding to the limit value, and thus the lost power of the powergenerator 6 is relatively large. In contrast, at the time T2 included inthe period P3, the suppression is only down to the power equivalent tothe total consumed power Pc, and thus the lost power of the powergenerator 6 is relatively small. Thus the lost power can be decreasedduring PV suppression if the total consumed power Pc is increased so asto exceed the limit value.

Further, at the time T1 included in the period P2, the output power Pgfrom the power generator 6 suppressed down to the power corresponding tothe limit value is larger than the total consumed power Pc of the homeH, and thus power corresponding to the difference (Pg minus Pc) is inexcess as excess power. This excess power is sold to the commercialelectrical power system 8 as the reverse flow power. In contrast, at thetime T2 included in the period P3, the output power Pg from the powergenerator 6 is equivalent to the total consumed power Pc of the home H,and thus power is neither sold nor purchased.

The control device 2 is described next. As illustrated in FIG. 4 , thecontrol device 2 includes a controller 21, a storage 22, a timer 23, anin-home communication device 24 and an outside-home communication device25. Each of these components is connected via a bus 29.

The controller 21 includes (all non-illustrated) components such as aCPU, a ROM, and a RAM. The “CPU” is also termed a central processor,central calculator, processor, microprocessor, microcomputer, digitalsignal processor (DSP), or the like. The controller 21 performs overallcontrol of the control device 2 by the CPU reading a program and datastored in the ROM, and using the RAM as a working area.

The storage 22 is nonvolatile semiconductor memory such as a flashmemory, an erasable programmable ROM (EPROM), an electrically erasableprogrammable ROM (EEPROM), or the like, and acts as a so-calledsecondary storage device (auxiliary storage device). The storage 22storage stores various types of programs and data used by the controller21 for various types of processing, as well as various types of datagenerated or acquired by the controller 21 performing the various typesof processing.

The timer 23 includes a real time clock (RTC) and is a time-measuringdevice that continues to measure time even during periods when power isturned off to the control device 2.

The in-home communication device 24 includes a network interface card(NIC) controller for communication via a wireless network installed inthe home H, and under control of the controller 21, communicates via thewireless network with each of the power measurement device 4, the waterheater 5, the power generator 6, and the apparatus 7. Further, under thecontrol of the controller 21, the in-home communication device 24communicates with the operating terminal 3 via Wi-Fi (registeredtrademark), Wi-SUN (registered trademark), wireless LAN, or the like.

The outside-home communication device 25, via the router 12, isconnected to the wide area network N such as the Internet, for example.The outside-home communication device 25 communicates with the dataserver 13, the power server 14, and the like via the wide area networkN.

Functional configuration of the control device 2 is described next withreference to FIG. 5 . As illustrated in FIG. 5 , the control device 2functionally includes a terminal communicator 200, an instructionacquirer 201, a measurement value acquirer 202, a relay unit 203, adetermination unit 205, a consumed power calculator 206, a generatedpower estimator 207, and a water heater controller 208. Each of thesefunctions is achieved by software, firmware, or a combination ofsoftware and firmware. The software and firmware are recorded asprograms and are stored in the storage 22 or in the ROM within thevarious apparatuses. Further, the controller 21 achieves the function ofeach of the components by the CPU executing the programs stored in theROM or the storage 22.

Further, the control device 2 includes an instruction storage 210, ameasurement value storage 220, and a setting storage 230. Theinstruction storage 210, the measurement value storage 220, and thesetting storage 230 are constructed in memory regions within the storage22.

The terminal communicator 200 communicates with the operation terminal 3via the in-home communication device 24. FIG. 6 illustrates a specificexample of a setting screen displayed by the operating terminal 3. Theterminal communicator 200 functions as a display controller to cause adisplay device of the operating terminal 3 to display the setting screenillustrated in FIG. 6 . In the setting screen illustrated in FIG. 6 ,the user, who is the power consumer, can set various types of modes viaan input device of the operating terminal 3.

For example, “solar output suppression-coordinated mode” is a mode thateffectively uses the lost power of the power generator 6 duringsuppression of PV power by coordinated control of the water heater 5during PV suppression. The user can make activate this function bysetting ON the item “solar output suppression-coordinated control” thatoccurs in the “solar output suppression-coordinated mode”. Upon settingON of the item “solar output suppression coordinated control”, theoperating terminal 3 transmits setting information indicating thecontents of such setting to the control device 2. The terminalcommunicator 200 of the control device 2 functions as a settinginformation receiver that receives setting information transmitted fromthe operating terminal 3. The controller 21 operates cooperatively withthe in-home communication device 24 to achieve the terminal communicator200 function. The setting information received by the terminalcommunicator 200 is stored in the setting storage 230.

The instruction acquirer 201 acquires an instruction to, in thespecified period, suppress the supplying, to the commercial electricalpower system 8, of power from the power generator 6 that supplies powerto the specified power-consuming area. The expression “specifiedpower-consuming area” is specifically the home H and the groundsthereof, and is the site that receives the supply of power, and consumesthe received power, from the commercial electrical power system 8 andfrom the power generator 6 installed at the home H. The expression “aninstruction to suppress the supplying in the specified period” means theinstruction (suppression instruction) for PV suppression distributedfrom the power server 14 as described previously.

Upon the power server 14 distributing the suppression instruction, theinstruction acquirer 201 acquires the distributed suppressioninstruction via the wide area network N. Upon the instruction acquirer201 acquiring the suppression instruction, the content of the PVsuppression, such as the limit value and the schedule designated by theacquired suppression instruction, are stored in the instruction storage210. The controller 21 operates cooperatively with the outside-homecommunication device 25 to achieve the instruction acquirer 201function.

The instruction storage 210 stores the content of the suppressioninstruction acquired by the instruction acquirer 201. The expression“content of the suppression instruction” means specifically the limitvalue and the schedule of the PV suppression designated by thesuppression instruction. The instruction storage 210 updates the limitvalue and the schedule of the stored PV suppression each time theinformation acquirer 201 acquires the suppression instruction from thepower server 14.

The measurement value acquirer 202 acquires, via the in-homecommunication device 24, the measurement value of the power obtained bythe power measurement device 4 from the power measurement device 4.Specifically, the measurement value acquirer 202 acquires: a measurementvalue of the power Pg supplied to the home H from the power generator 6,a measurement value of the power Pb supplied to the home H from thecommercial electrical power system 8, and a measurement value of thepower Pe supplied to the water heater 5.

The power measurement device 4 sends periodically, for example, themeasurement values of the power Pb, Pg, and Pe transmitted through thepower lines D1 to D3 and obtained by the CT1 to CT3 to the controldevice 2. Alternatively, the measurement value acquirer 202 may, asrequired, transmit to the power measurement device 4 a request for themeasurement values of the power Pb, Pg, and Pe, and the powermeasurement device 4 may transmit to the control device 2 themeasurement values of the power Pb, Pg, and Pe in the format of a replyto this request. In this manner, the controller 21 operatescooperatively with the in-home communication device 24 to achieve themeasurement value acquirer 202 function.

The measurement value storage 220 stores the measurement values of thepower Pb, Pg, and Pe acquired by the measurement value acquirer 202.Every time the measurement value acquirer 202 acquires the measurementvalues of the power Pb, Pg, and Pe obtained by the power measurementdevice 4, the measurement value storage 220 stores the acquiredmeasurement values and builds a database.

FIG. 7 illustrates a specific example of a power database 40 stored inthe measurement value storage 220. As illustrated in FIG. 7 , the powerdatabase 40 stores, as a time series in chronological order, the poweramount of the purchased power Pb, the power amount of the output powerPg of the generated power, the power amount of the total consumed powerPc of the home H obtained by adding together the power Pb and the powerPg, and the power amount of the consumed power Pe of the water heater.

Upon acquiring the measurement values of the power Pb, Pg, and Pe fromthe power measurement device 4, the measurement value acquirer 202calculates the respective power amounts and stores the calculated poweramounts consecutively in the power database 40. Here, the term “poweramount” means a value of power integrated over a predetermined period.Specifically, the measurement value acquirer 202 integrates over 30minutes, which is the incremental unit of the schedule of the PVsuppression, the measurement values of the power Pb, Pg, and Pe from thepower measurement device 4 and the sum of the power Pb and the power Pg.In this manner, the measurement value acquirer 202 acquires the poweramounts in 30 minute increment units for each of the measurement valueof the purchased power Pb, the measurement value of the output power Pgof the generated power, the measurement value of the consumed power(total consumed power) Pc of the home H obtained as the sum of the powerPb and the power Pg, and the measurement value of the consumed power Peof the water heater, and the measurement value acquirer 202 stores theseacquired power amounts in the power database 40 every 30 minutes.

Further, in the case in which the measurement value of the power Pgsupplied to the home H from the power generator 6 is acquired as thepower amount, the measurement value acquirer 202 functions as a firstmeasurement value acquirer. In the case in which the measurement valueof the consumed power Pc (equal to Pb plus Pg) of the home H is acquiredas the power amount, the measurement value acquirer 202 functions as asecond measurement value acquirer. In the case in which the measurementvalue of the consumed power Pe of the water heater 5 is acquired as thepower amount, the measurement value acquirer 202 functions as a thirdmeasurement value acquirer. Hereinafter, the processing of thedetermination unit 205, the consumed power calculator 206, and thegenerated power estimator 207 is executed using the measurement valuesof the power Pb, Pg, Pe, and Pc stored as the power amounts in the powerdatabase 40.

The relay unit 203 relays to the PV-PCS 11 of the power generator 6 viathe in-home communication device 24 the content of the suppressioninstruction acquired by the instruction acquirer 201. Further, the relayunit 203 relays the measurement value of the power Pb, Pg, and Peacquired by the measurement value acquirer 202 to the PV-PCS 11 of thepower generator 6 via the in-home communication device 24. In thismanner, the controller 21 achieves the relay unit 203 functioncooperatively with the in-home communication device 24.

In the case in which the suppression instruction is acquired by theinstruction acquirer 201, the determination unit 205 determines whethera predetermined condition is satisfied to command the water heater 5 toperform the water heat-up operation in the specified period designatedby the suppression instruction. The “predetermined condition to commandthe water heater 5 to perform the water heat-up operation” is acondition for determining whether the water heat-up operation of thewater heater 5 can efficiently use the lost power that occurs during theperiod of suppression, by the PV suppression, of power output from thepower generator 6. Since the water heat-up operation of the water heater5 generally has high consumed power in comparison to the use of theother apparatuses, the water heat-up operation of the water heater 5 isused due to the ability to efficiently use the lost power. Thecontroller 21 achieves the determination unit 205 function. Thedetermination processing of the determination unit 205 is described indetail hereinafter with reference to FIG. 8 .

FIG. 8 illustrates a specific example of: a relationship between theconsumed power Pc and the generated power Pa during the suppression ofPV power, and timing of the water heat-up operation to be performed bythe water heater 5. Similarly to the example illustrated in FIG. 2 andFIG. 3 , the solid-line plot La in FIG. 8 indicates transitioning of thegenerated power Pa from the power generator 6 occurring when there is noprior instruction for PV suppression, and the dashed-line plot Lpindicates transitioning of the limit value of the output power Pg fromthe power generator 6 designated by the suppression instruction.Further, the dot-dashed-line plot Lc indicates the transitioning of thetotal consumed power Pc of the home H, and the bold solid-line plot Lgindicates the transitioning of the output power Pg from the powergenerator 6. However, for ease in understanding of the exampleillustrated in FIG. 8 , the limit value of the output power Pg indicatedby the dashed-line plot Lp is described for a case in which the limitvalue is constant in all regions.

As illustrated in FIG. 8 , in the period from a time A to a time Fduring the period from a time H to a time I when power is generated bythe power generator 6 (in other words, the generated power Pa ispositive), the generated power Pa is larger than the consumed power Pcof the home H. Thus in the period from the time A to the time F, poweris not purchased from the commercial electrical power system 8. Further,in the period from the time A to a time D, the consumed power Pc of thehome H is less than the limit value. Thus in the period from the time Ato the time D, the output power Pg from the power generator 6 issuppressed to the limit value, and power is sold from the home H to thecommercial electrical power system 8. In contrast, in the period fromthe time D to the time F, the consumed power Pc of the home H is largerthan the limit value. Thus in the period from the time D to the time F,the output power Pg from the power generator 6 is suppressed to thetotal consumed power Pc within the home H, and power is neither sold norpurchased.

The determination unit 205 determines, as first determinationprocessing, whether a first condition is satisfied. This first conditionis satisfied in the case in which power is not being supplied to thehome H from the commercial electrical power system 8, that is to say, inthe case in which power is not being purchased from the commercialelectrical power system 8. The determination unit 205, on the basis ofthe measurement value of the power Pb acquired by the measurement valueacquirer 202, determines whether power is being purchased from thecommercial electrical power system 8. In the case in which power isbeing purchased, there is neither excess power nor generation loss, andthus causing operation of the water heater 5 is not required.

Specifically, the determination unit 205 determines whether the poweramount of the power Pb stored last in the power database 40 is greaterthan or equal to a predetermined threshold α. The threshold α is amargin that takes into account a possibility that the sold power amountcan, depending on conditions, increase instantaneously during the saleof power, and this threshold α is a small positive value, such as 50 Wh.A period D1, from the time A to the time F indicated in FIG. 8 , isidentified by the first determination processing.

The determination unit 205 determines, as second determinationprocessing, whether a second condition is satisfied. This secondcondition is satisfied in the case in which the power Pg supplied fromthe power generator 6 to the home H is larger than a limit valuedetermined in accordance with the suppression instruction. Thedetermination unit 205 determines whether the measurement value of thepower Pb acquired by the measurement value acquirer 202 is larger thanthe limit value determined in accordance with the suppressioninstruction.

Two cases are considered in which this second condition is notsatisfied. In one case, weather occurring in the execution period of PVsuppression is poor such that the power generation amount of the powergenerator 6 does not reach the suppression amount, that is, the power Pgis less than the limit value. In this case, a state occurs in which thepower generator 6 is not suppressing output, and thus there is nooccurrence of the power generation loss. In the other case, the outputpower Pg from the power generator 6 is suppressed to the limit value,that is, the power Pg=the limit value, for example, as in the periodfrom the time A to the time D indicated in the FIG. 8 . In this case,the excess power is sold to the commercial electrical power system 8.Thus diversion of this portion of power to the water heater 5 until thestoppage of the sale of power is not economically efficient from thestandpoint of the power consumer. Power is not being sold in period D2the period in which the second condition is satisfied and the outputpower PG from the power generator 6 is greater than the limit value, andthus the sale of power is not prevented even if the water heater 5 isoperated.

That is to say, the determination unit 205 determines whether the poweramount of the power Pg stored last in the power database 40 is greaterthan or equal to a value obtained by adding a threshold β to thesuppression amount, that is, determines whether the present output poweramount of the power generator 6 substantially exceeds the suppressionamount. The threshold β is a margin that takes into account existence ofsomewhat of a mismatch in the adjustment of output of the PV-PCS 11 inreal time, and thus this threshold is a small positive value, such as100 Wh. The period D2 is identified by the second determinationprocessing to be from the time D to a time G indicated in FIG. 8 .

The determination unit 205 determines, as third determinationprocessing, whether a third condition is satisfied. This third conditionis satisfied in the case in which the consumed power of the home H whenthe water heater 5 performs the water heat-up operation is smaller thanthe generated power Pa generated by the power generator 6. For example,in the case in which the consumed power of the home H when the waterheater 5 performs the water heat-up operation is larger than thegenerated power Pa capable of being output by the power generator 6, thepurchase of power is required for the water heater 5 to perform thewater heat-up operation. The allowing of the water heater 5 to performthe water heat-up operation until power is purchased cannot be efficientfrom the standpoints of the environment and the economics of the powerconsumer. Thus the determination unit 205 determines, as the thirddetermination processing, whether the consumed power of the home Hoccurring when the water heater 5 performs the water heat-up operationis smaller than the generating power Pa generated by the power generator6, that is to say, determines whether the water heater 5 can perform thewater heat-up operation even without the purchase of power.

In order to execute the third determination processing, the consumedpower calculator 206 calculates, on the basis of the measurement valuesof the power Pc and the power Pe stored in the power database 40, theconsumed power of the home H occurring when the water heater 5 performsthe water heat-up operation. Further, the generated power estimator 207estimates the generated power Pa generated by the power generator 6 onthe basis of the measurement value of the power Pg stored in the powerdatabase 40. The consumed power calculator 206 and the generated powerestimator 207 are each achieved by the controller 21 operating incooperation with the storage 22.

Specifically, the consumed power calculator 206 calculates the consumedpower of the home H occurring when the water heater 5 performs the waterheat-up operation (referred to hereinafter as Pc′) by firstlysubtracting, from the measurement value of the consumed power Pc of thehome H prior to the water heater 5 executing the water heat-upoperation, the measurement value of the consumed power Pe of the waterheater 5 occurring prior to the water heater 5 executing the waterheat-up operation, further adding a rated value R of the consumed powerof the water heater 5. That is to say, the following relationshipformula is established: Pc′=Pc−Pe+R.

The measurement value of the consumed power Pc and the measurement valueof the consumed power Pe of the water heater 5 of the home H occurringprior to the water heater 5 executing the water heat-up operation areacquired by the measurement value acquirer 202 functioning as the secondmeasurement value acquirer and the third measurement value acquirer,respectively, and these measurement values are stored as power amountsin the power database 40. The consumed power calculator 206 refers tothe measurement values of the power Pc and the power Pe stored last inthe power database 40. Further, the consumed power Pe of the waterheater 5 is a value near zero if the water heater 5 is not operating,and this value corresponds to execution of some operation by the waterheater 5 if such execution is in progress.

The rated value R of the consumed power of the water heater 5 is themaximum power amount expected to be consumed by the water heater 5 whenthe water heater 5 performs the water heat-up operation. The rated valueR is specified beforehand in accordance with various types of conditionssuch as a heat-up temperature, a hot water storage amount, and the like,and this value is stored beforehand in storage means of the water heater5 or in the storage 22 of the control device 2. If the rated value R isstored in the water heater 5, the consumed power calculator 206 acquiresthe rated value R corresponding to the water heat-up operation to beperformed, as may be required, from the water heater 5 via the in-homecommunication device 24.

The consumed power calculator 206 subtracts the measurement value of theconsumed power Pe of the water heater 5 from the measurement value ofthe total consumed power Pc of the home H acquired in the aforementionedmanner, and further adds the rated value R of the water heater 5, tocalculate the consumed power Pc′ of the home H forecast for when thewater heater 5 performs the water heat-up operation. This consumed powerPc′, as indicated by the double-dot-dashed line Lc′ in FIG. 8 ,illustrates transitioning that is the transitioning of the totalconsumed power Pc with a fixed offset added thereto.

Secondly, the generating power Pa generated by the power generator 6 canbe acquired by using the CT2 arranged in the power line D2 to measurethe output power Pg from the power generator 6 during the period when PVsuppression is not being executed. However, measurement of the panelgenerated power cannot be performed during the period of execution ofthe PV suppression, and thus the generated power Pa cannot be acquireddirectly. Thus the generated power estimator 207 uses a past powergeneration amount result as the estimated value of the present generatedpower Pa. Specifically, the generated power estimator 207 estimates, asthe generated power Pa from the power generator 6 occurring in theexecution period of the PV suppression, the output power Pg from thepower generator 6 occurring during the period (period prior to thespecified period of execution of the PV suppression) when the PVsuppression is not executed.

The measurement value of the output power Pg from the power generator 6occurring in the period prior to the specified period for execution ofthe PV suppression is acquired by the measurement value acquirer 202functioning as the first measurement value acquirer and is stored as apower amount in the power database 40. The generated power estimator 207estimates the generated power Pa using, among the measurement values ofthe power Pg stored in the power database 40, the measurement value ofthe output power Pg supplied to the home H from the power generator 6 inthe same time slot as a designated time slot for execution of the PVsuppression and that occurs in several days (past C days) prior to aspecified day for execution of the PV suppression.

Here, the expression “same time slot” means a time slot that starts atthe same time of day as the start time of the PV suppression and ends ata time of day that is the same as the end time of the PV suppression. Ifthe time slots during the day are the same, solar insolation is roughlythe same, and thus the power generation amount from solar powergeneration is estimated to be about the same, so the measurement valuesoccurring at the same time slot as the specified time slot for executionof the PV suppression are used.

FIG. 9 illustrates an example of transitioning of the measurement valuesof the output power from the power generator during a three day periodprior to the day in which the PV suppression is executed. In the exampleof FIG. 9 , on the day one day prior to the day of execution of the PVsuppression, the output power amount from the power generator 6 is lowin the morning and becomes high in the evening. In contrast, on the daytwo days prior to the day of execution of the PV suppression, the powergeneration amount from sunlight is low all day long. Further, on the daythree days prior to the day of execution of the PV suppression, theoutput power amount from the power generator is high in the morning andbecomes low in the afternoon. In this manner, the output power amountfrom the power generator 6 is affected by weather during the day.

For each time included in the specified time slot for execution of thePV suppression, the generated power estimator 207 estimates, as thegenerated power Pa occurring at the time of day when PV suppression isexecuted, the maximum value of measurement values acquired in theprevious C days by the measurement value acquirer 202. For example, ineach of the previous C days, if the measurement value of the outputpower Pg occurring at the X-th day among the previous C days is maximumamong the measurement values of the output power Pg measured in a firstperiod included in the same time slot as the specified time slot ofexecution of the PV suppression, the generated power estimator 207estimates that the measurement value of the output power Pg occurring onthe X-th day is the generated power Pa occurring in the first period ofthe day of execution of the PV suppression. Further, in each of theprevious C days, if the measurement value of the output power Pgoccurring at the Y-th day among the previous C days is maximum among themeasurement values of the output power Pg measured in a second periodincluded in the same time slot as the specified time slot of executionof the PV suppression, the generated power estimator 207 estimates thatthe measurement value of the output power Pg occurring on the Y-th dayis the generated power Pa occurring in the second period of the day ofexecution of the PV suppression.

FIG. 10 illustrates the transitioning of the maximum values (movement ofmaximum values) among the measurement values of the output power fromthe power generator occurring during the three day period prior to theday of execution of the suppression of PV power as illustrated in FIG. 9. The generated power estimator 207, on the basis of the measurementresults of the output power Pg of the previous three days illustrated inFIG. 9 , estimates that the value of the transitioning illustrated inFIG. 10 is the generated power Pa occurring in each of the periods ofthe day in which the PV suppression is executed. The maximum values ofthe measurement values of the output power Pg in each period are used,for estimation of an upper limits of power generation from sunlight dueto the days when the PV suppression is executed, because such days arenormally days of clear weather when the reverse flow power isanticipated to be high, and thus power from sunlight is anticipated tobe generated at the maximum limit. The number of past C days is set soas to include at least a day of clear weather when the PV suppression isnot executed, for example, such as being set to a consecutive ten daysto two weeks immediately prior to the day of execution of the PVsuppression.

The determination unit 205 uses the consumed power Pc′ calculated by theconsumed power calculator 206 and the generated power Pa estimated bythe generated power estimator 207 to execute the third determinationprocessing for the specified period when there is the instruction forthe PV suppression. That is to say, the determination unit 205determines whether the consumed power Pc′ of the home H when the waterheater 5 performs the water heat-up operation is smaller than thegenerated power Pa generated by the power generator 6. The period D3from a time B to a time E (E′) illustrated in FIG. 8 is determined bythe third determining processing.

If there is prior acquisition of the suppression instruction by theinstruction acquirer 201, in the specified period of the instruction forthe PV suppression, when the determination unit 205 determines that thepredetermined conditions are satisfied, the water heater controller 208commands the water heater 5 to heat water.

The predetermined conditions are the three conditions occurring in theaforementioned first through third determination processing by thedetermination unit 205, and when these three conditions are allsatisfied, the predetermined conditions are satisfied. Specifically, thepredetermined conditions are satisfied when: (1) power is supplied tothe home H from the commercial electrical power system 8, (2) the powerPg supplied to the home H from the power generator 6 is higher than thelimit value determined in accordance with the suppression instruction,and (3) the consumed power of the home H occurring when the water heater5 performs the water heat-up operation is lower than the generated powerPa generated by the power generator 6. The time slot when all of thesethree conditions is satisfied is a period D4 from the time D (D′) to thetime E (E′) in the example illustrated in FIG. 8 .

In this manner, the water heater controller 208 commands the waterheater 5 to heat water in at least a portion of the periods in which,within the specified period for which there is the instruction for PV,the predetermined conditions are satisfied. Specifically, the waterheater controller 208 transmits to the hot water supply controller 54 ofthe water heater 5 via the in-home communication device 24 a PVsuppression-permitting trigger indicating permission for the waterheat-up operation. However, when the predetermined conditions are notsatisfied within the specified period in which PV suppression iscommanded, the water heater controller 208 commands the water heater 5to end the water heat-up operation. Specifically, the water heatercontroller 208 transmits to the hot water supply controller 54 of thewater heater 5 via the in-home communication device 24 a PVsuppression-cancellation trigger indicating cancellation of the waterheat-up operation. In this manner, the function of the water heatercontroller 208 is achieved by the controller 21 in cooperation with thein-home communication device 24.

In the execution period of the PV suppression, if the predeterminedconditions are satisfied, the water heater controller 208 repeatedly ina predetermined cycle transmits to the hot water supply controller 54this type of command. The predetermined cycle, for example, has unitsthat are the same as those of the schedule for PV suppression, such as30 minutes. By periodic transmission of the command at a fixed cycle,the command can be reliably transmitted to the water heater 5 even whenmomentary breakdowns occur in the transmission of the command.

Upon receiving the command for the water heat-up operation, the hotwater supply controller 54 performs the water heat-up operation inaccordance with the received command from the water heater controller208. Specifically, the hot water supply controller 54 controls the heatpump unit 50 so as to generate hot water of the desired heat-uptemperature within the hot water storage tank 53. Various types ofconditions occurring in the water heat-up operation, such as the heat-uptemperature and the hot water storage amount, for example, are specifiedby the user via the remote controller 55.

Further, the water heater controller 208 transmits the command withouttaking into account the condition of the water heater 5, and thus thereare cases in which the hot water supply controller 54 does not operatein accordance with the received command. For example, the hot watersupply controller 54, upon receiving an command to further perform thewater heat-up operation when the water heater 5 is already executing thewater heat-up operation, discards the command. In the same manner, thehot water supply controller 54, upon receiving an command to stop thewater heat-up operation when the water heater 5 is already not executingthe water heat-up operation, discards the command. The number of heat-upoperations performed on a single day is set to one per day, for example,in consideration of working life of the compressor. Thus upon receivingthe command once to perform the water heat-up operation and thenexecuting the water heat-up operation, the hot water supply controller54 does not perform the water heat-up operation for a second time eventhough a water heat-up operation is received at another time on the sameday. Further, in the case of reception of a control command for thewater heater 5 via the remote controller 55 from the user, the hot watersupply controller 54 prioritizes the control command from the user.

The result of the control of the water heater 5 by the water heatercontroller 208 is displayed via the operating terminal 3. FIG. 11illustrates a specific example of a display screen displayed by theoperating terminal during the PV suppression. In the period of executionof the PV suppression, as illustrated in FIG. 11 , the terminalcommunicator 200 functions as a controller to cause the display deviceof the operating terminal 3 to display notification informationincluding an apparatus listing, an apparatus layout, messages indicatingthe present status, and the like.

Specifically, the terminal communicator 200 displays a PV suppressiongraphic 31 indicating that PV suppression is in progress, and alsodisplays amounts of the generated power, the consumed power, the chargedpower, and the sold power. Further, during the PV suppression, theterminal communicator 200 displays in the vicinity of a graphic of thewater heater 5, which is the apparatus targeted for coordinated control,a coordinated control graphic 32 indicating that coordinated control isbeing executed. Due to such display, the user can visually confirmvarious types of information occurring during the PV suppression.

Processing executed by the energy management system 1 configured in theaforementioned manner is described with reference to FIG. 12 to FIG. 14.

A summary of the processing executed by the energy management system 1is illustrated in FIG. 12 . FIG. 12 illustrates the processing executedby the power server 14, the control device 2, the power generator 6 andthe water heater 5, after a PV suppression instruction is transmittedonce from the power server 14 until completion of execution of such PVsuppression. In the case in which the instruction for the PV suppressionis transmitted from the power server 14 multiple times, the processingillustrated in FIG. 12 is executed in parallel for each of the multiplePV suppressions.

Further, although the power measurement device 4 and the operatingterminal 3 are not illustrated in FIG. 12 , during the period ofexecution of the processing illustrated in FIG. 12 , the powermeasurement device 4 by the CT1 through CT3 measures the power sentthrough the power lines D1 through D3, and sequentially transmits to thecontrol device 2 the measurement values of the measured power. Further,the operating terminal 3 by the setting screen illustrated in FIG. 6receives a setting from the user for solar output suppressioncoordinated control and transmits to the control device 2 content of thereceived setting.

Upon determination of the execution of the PV suppression andconfirmation of the schedule and detailed contents thereof, the powerserver 14 distributes to each power consumer the instruction(suppression instruction) for the PV suppression (step S1). Upondistribution of the suppression instruction from the power server 14,the control device 2 acquires the distributed suppression instructionvia the wide area network N. Upon acquiring of the suppressioninstruction, the control device 2 forwards the acquired suppressioninstruction to the PV-PCS 11 of the power generator 6 via the wirelessnetwork installed in the home H (step S2).

Upon acquiring the suppression instruction forwarded from the controldevice 2, the PV-PCS 11 executes, in accordance with the acquiredsuppression instruction, suppression of the output of the generatedpower generated by the power generator 6 (step S3). FIG. 13 illustratesdetails of the output suppression processing of the PV-PCS 11 executedin the step S3. This output suppression processing is executedrepeatedly in a fixed cycle during the period in which power is suppliedto the PV-PCS 11. The fixed cycle is one minute long, for example.

In the output suppression processing illustrated in FIG. 13 , the PV-PCS11 determines firstly whether the present time is included in anexecution period of the PV suppression as designated in accordance withthe suppression instruction (step S301). Further, if there is nosuppression instruction, the determination of step S301 is NO.

When the present time is determined not to be included in the executionperiod of the PV suppression (NO in step S301), the PV-PCS 11 operatesin a normal mode (step S302). The normal mode is a mode in which allgenerated power capable of being output, without suppression of outputpower from the power generator 6, is supplied to the home H or thecommercial electrical power system 8. Thereafter, the PV-PCS 11 ends theoutput suppression processing.

However, when the present time is determined to be included in theexecution period of the PV suppression (YES in step S301), the PV-PCS 11secondly determines whether the output power Pg presently output fromthe power generator 6 is larger than a limit value (step S303).

If the determination is that the output power Pg presently output fromthe power generator 6 is not larger than the limit value (NO in stepS303), such as when the power generation amount from sunlight is smalldue to cloudy weather or rain, for example, then output power Pg fromthe power generator 6 does not require suppression. Thus processing bythe PV-PCS 11 goes to step S302, and the PV-PCS 11 operates in thenormal mode.

However, if the determination is that the output power Pg presentlyoutput from the power generator 6 is larger than the limit value (YES instep S303), the PV-PCS 11 determines whether power is being suppliedfrom the commercial electrical power system 8, that is to say,determines whether power is being purchased from the commercialelectrical power system 8 (step S304). The PV-PCS 11 acquires the valueof the power Pb calculated by the CT1, and determines whether the valueof the power Pb is positive, thereby determining whether power is beingsupplied from the commercial electrical power system 8.

If the determination is that power is not being supplied from thecommercial electrical power system 8 (NO in step S304), the PV-PCS 11operates in an output suppression mode (step S305). The outputsuppression mode is a mode that suppresses the output power Pg from thepower generator 6 to the limit value as instructed in accordance withthe suppression instruction. Such operation corresponds to the case inwhich the total consumed power Pc of the home H is smaller than thelimit value so that excess power is occurring, for example, as in theperiod P2 illustrated in FIG. 3 . Thereafter, the PV-PCS 11 ends theoutput suppression processing.

If the determination is that power is being supplied from the commercialelectrical power system 8 (YES in step S304), the PV-PCS 11 operates ina reverse flow power zero mode (step S306). The reverse flow power zeromode is a mode that adjusts the output power Pg from the power generator6 so that the reverse flow power approaches zero as much as possible.Such operation corresponds to the case in which purchasing of power fromthe commercial electrical power system 8 is required when the totalconsumed power Pc of the home H is greater than the limit value so thatexcess power does not occur (such as in the period P3 illustrated inFIG. 3 , for example), that is, when the output power Pg from the powergenerator 6 is suppressed to the limit value. In this case, the PV-PCS11 adjusts the output power Pg from the power generator 6 so as tobecome equal to the total consumed power Pc. Thus the power Pb measuredby the CT1 becomes as close as possible to zero so that power is neitherpurchased nor sold. Thereafter, the PV-PCS 11 ends the outputsuppression processing.

The overall processing of the energy management system 1 illustrated inFIG. 12 is further described below. Upon the control device 2 forwardingthe suppression instruction acquired from the power server 14 to thepower generator 6, the control device 2 determines whether there isarrival of a start time for the PV suppression (step S4). If the arrivalof the start time for the PV suppression is pending (NO in step S4), thecontrol device 2 waits until the arrival of the start time.

However, if there is arrival of the start time of the PV suppression(YES in step S4), the control device 2 executes PV suppressiondetermination in accordance with the acquired suppression instruction(step S5). Details of the PV suppression determination processingexecuted in step S5 are illustrated in FIG. 14 . This PV suppressiondetermination processing is executed repeatedly in a fixed cycle whenthe solar output suppression coordinated control is set ON in thesetting screen illustrated in FIG. 6 and there is arrival of thedesignated execution period for the PV suppression in accordance withthe suppression instruction. The fixed cycle length, for example, is 30minutes, which is the same incremental unit as that of the schedule ofthe PV suppression.

In the PV suppression determination processing illustrated in FIG. 14 ,the controller 21 of the control device 2, as the first determinationprocessing, determines whether the purchased power amount is presentlyless than or equal to the threshold α, that is, whether power issubstantially being purchased at present (step S501). The presentpurchased power amount is obtained by referring to the measurement valueof the power Pb acquired by the measurement value acquirer 202 and laststored in the power database 40. The processing of step S501 determineswhether the present time is included in the period D1 illustrated inFIG. 8 .

If the determination is that power is not being substantially purchasedat present (YES in step S501), the controller 21 determines, as thesecond determination processing, whether the present output power amountof the power generator 6 is greater than or equal to a value obtained byadding the threshold β to the suppression amount, that is, whether thepresent output power amount of the power generator 6 substantiallyexceeds the suppression amount (step S502). The present output poweramount of the power generator 6 is obtained by referring to themeasurement value of the power Pg acquired by the measurement valueacquirer 202 and last stored in the power database 40. Further, thesuppression amount is a value expressed in power amount units bymultiplying the limit value determined in accordance with thesuppression instruction by the time of 30 minutes, which is theincremental unit of the schedule of the PV suppression. The processingof step S502 determines whether the present time is included in theperiod D2 illustrated in FIG. 8 .

When the determination is that power is not presently beingsubstantially purchased (NO in step S501), excess power is notoccurring. Further, when the determination is that the output poweramount of the power generator 6 presently is not substantially exceedingthe suppression amount (NO in step S502), sale of power is occurring.Thus in this case causing operation of the water heater 5 is determinednot be necessary, and the controller 21 ends the PV suppressiondetermining processing.

If the determination in step S502 is that the output power of the powergenerator 6 at present substantially exceeds the suppression amount (YESin step S502), the controller 21 determines a presently set ON-OFFstatus of a PV suppression flag (step S503). The “PV suppression flag”is a flag indicating to the water heater 5 an instruction condition ofthe PV suppression, and is stored, for example, in the storage 22 of thecontrol device 2. In the immediately prior PV suppression determinationprocessing, the PV suppression flag is set ON when the PVsuppression-permitting trigger is transmitted to the water heater 5, andis set OFF when the PV suppression-cancellation trigger is transmittedto the water heater 5. The below-described third determinationprocessing of the controller 21 is executed using conditions that differin accordance with the ON-OFF status of the PV suppression flag aspresently set.

When the PV suppression flag is set ON (YES in step S503), thecontroller 21, as the third determination processing, determines whetherthe past actual power generation amount is larger than a value obtainedby adding the threshold γ to the consumed power amount of the home Hduring heat-up operation of the water heater 5 (step S504). The pastactual power generation amount is the amount of the generated power Paestimated by the generated power estimator 207, and as describedpreviously, is obtained by acquiring the measurement value, for theprevious C days, of the power Pg supplied to the home H from the powergenerator 6 in the time slot that is the same as the time slot specifiedfor execution of the PV suppression. Further, the consumed power amountof the home H during the water heat-up operation of the water heater 5is the amount of the power Pc′ calculated by the consumed powercalculator 206, and this consumed power amount is calculated in theaforementioned manner by subtracting the measurement value of theconsumed power Pe of the water heater 5 from the measurement value ofthe total consumed power Pc of the home H stored in the database 40, andthen adding the consumed power of the water heater 5 occurring when thewater heater 5 performs the water heat-up operation.

Further, the past actual power generation amount used in thedetermination is fundamentally an estimate of the present actual powergeneration amount, and thus the threshold γ is a margin for securingsafety and is set such that the consumed power does not exceed the powergeneration amount that the power generator 6 is capable of outputting.

If the setting of the PV suppression flag is OFF (NO in step S503), thecontroller 21 determines, as the third determination processing, whetherthe past actual power generation amount is larger than a value obtainedby adding a threshold γ′ to the consumed power amount of the home Hduring the water heat-up operation of the water heater 5 (step S505).That is to say, the controller 21 uses a threshold as the margin thatdiffers in accordance with the ON-OFF status of the PV suppression flagas presently set.

The threshold γ′ is a margin for securing safety and is set, in the samemanner as the threshold γ, such that the consumed power amount does notexceed the power generation amount capable of output from the powergenerator 6. The threshold γ′ is set to a value larger than thethreshold γ. Specifically, as illustrated in FIG. 15 , the threshold γ′in the case in which the PV suppression flag is switched from OFF to ONis set to a value somewhat larger than the threshold γ in the case inwhich the PV suppression flag is switched from ON to OFF. Thisconfiguration provides hysteresis when switching between ON and OFF.This is a countermeasure against so-called “flutter”, and is used forpreventing frequent switching due to the PV suppression determinationflag being set ON and OFF. In one example of threshold settings, thethreshold γ is set to 0 Wh, and the threshold γ′ is set to 200 Wh.Hereinafter, the threshold γ′ is termed the first threshold, and thethreshold γ is termed the second threshold.

More specifically, when the value obtained by adding the first thresholdγ′ to the total consumed power Pc′ of the home H occurring when thewater heater 5 performs the water heat-up operation is smaller than thegenerated power Pa generated by the power generator 6, the determinationunit 205 determines that the water heater 5 is to be commanded to heatwater. Then when the value obtained by adding the second threshold γ tothe total consumed power Pc′ of the home H occurring when the waterheater 5 performs the water heat-up operation is larger than thegenerated power Pa generated by the power generator 6, the determinationunit 205 determines that the water heater 5 is to be commanded to stopthe water heat-up operation. The water heater controller 208, inaccordance with the results of the determination by the determinationunit 205, commands the water heater 5 to perform the water heat-upoperation or stop the water heat-up operation.

By the processing of step S504 and step S505 in this manner,determination is made as to whether the present time is included in theperiod D4 illustrated in FIG. 8 . In the case of determination, in stepS504 and step S505, that the past actual power generation amount islarger than the value obtained by adding the predetermined γ or γ′ tothe consumed power amount of the home H during the water heat-upoperation of the water heater 5 (YES in step S504, YES in step S505),the controller 21 sets the PV suppression flag ON (step S506). Then thecontroller 21 transmits the PV suppression-permitting trigger to thewater heater 5 via the in-home communication device 24 (step S507).

In contrast, in the case of determination, in step S504 and step S505,that the past actual power generation amount is not larger than thevalue obtained by adding the predetermined γ or γ′ to the consumed poweramount of the home H during the water heat-up operation of the waterheater 5 (NO in step S504, NO in step S505), the controller 21 sets thePV suppression flag OFF (step S508). Then the controller 21 transmitsthe PV suppression-cancellation trigger to the water heater 5 via thein-home communication device 24 (step S509).

Upon transmission of the PV suppression-permitting trigger or the PVsuppression-cancellation trigger to the water heater 5, the controller21 ends the PV suppression determination processing illustrated in FIG.14 .

The overall processing of the energy management system 1 illustrated inFIG. 12 is further described below. As a result of the PV suppressiondetermination occurring in step S5, the water heater 5 receives thecontrol command transmitted from the control device 2. Specifically, thecontrol command is the PV suppression-permitting trigger or the PVsuppression-cancellation trigger. Upon reception of the control command,the water heater 5 answers the control device 2 by a reply to thereceived control command (step S6).

Then the water heater 5 updates the heating-up mode in accordance withthe received control command (step S7). Specifically, upon receiving thePV suppression-permitting trigger when the water heat-up operation isnot in progress, the hot water supply controller 54 of the water heater5 controls the heat pump unit 50 and performs the water heat-upoperation. Further, upon receiving the PV suppression-cancellationtrigger when the water heat-up operation is in progress, the hot watersupply controller 54 controls the heat pump unit 50 and stops the waterheat-up operation. Further, in the aforementioned manner, the hot watersupply controller 54 sometimes does not operate in accordance with thereceived command.

Upon execution of the PV suppression determination in step S5 andtransmission of the control command to the water heater 5, the controldevice 2 determines whether there is prior arrival of a completion timefor the PV suppression (step S8). In the case in which the arrival ofthe completion time for the PV suppression is pending (NO in step S8),the processing of the control device 2 returns to step S5. Then thecontrol device 2 executes the PV suppression determination atpredetermined time intervals (for example, 30 minutes), and transmits tothe water heater 5 the PV suppression-permitting trigger or the PVsuppression-cancellation trigger in accordance with the determinationresult. However, upon arrival of the completion time of the PVsuppression (YES in step S8), the processing illustrated in FIG. 12ends.

In the energy management system 1 in accordance with the presentembodiment as described above, when the predetermined first throughthird conditions are satisfied in the execution period of the PVsuppression, the control device 2 commands the water heater 5 to heatwater. Such operation enables a lowering of the power generation lossoccurring during the PV suppression and enables improvement of theutilization efficiency of power.

During such operation, the generated power Pa of the power generator 6occurring in the execution period of the PV suppression is estimated bythe control device 2 to be the measurement value of the power Pgsupplied to the home H from the power generator 6 occurring on a dayprior to the day of execution of the PV suppression. Due to use of theactual past power generation amount, the generated power Pa of the powergenerator 6 occurring in the execution period of the PV suppression canbe estimated with high precision without incurring a high calculationexpense.

Further, in the case in which the consumed power Pc′ of the home Hoccurring when the water heater 5 performs the water heat-up operationin the execution period of the PV suppression is smaller than thegenerated power Pa, the control device 2 commands the water heater 5 toheat water. In other words, the control device 2 compares the consumedpower Pc′ of the home H in the case in which the water heater 5 performsthe water heat-up operation and the generated power Pa that the powergenerator 6 is capable of outputting, obtains an estimate of how muchthe consumption amount consumed by the water heater 5 can be increased,and then commands the water heater 5 to heat water. As a result, withoutthe occurrence of power purchasing, the water heater 5 can be made toperform the water heat-up operation at a power corresponding to thepower generation loss. Particularly in the case in which there is acontract for time slot-specific fees, the power unit price is generallyhigh in the daytime when the PV suppression is executed, and thuseconomic losses can be effectively decreased by not allowing theoccurrence of power purchasing.

Modified Example

Although an embodiment of the present disclosure is described above,modifications and applications based on various aspects are possible inimplementing the present disclosure.

For example, in the aforementioned embodiment, the water heatercontroller 208 commands the water heater 5 to perform the water heat-upoperation in the case in which all of the predetermined first conditionthrough third condition are satisfied in the execution period of the PVsuppression. However, the water heater controller 208 may command thewater heater 5 to perform the water heat-up operation in the case inwhich only one or two of the conditions is satisfied among the firstcondition through third condition.

For example, in the case in which only the third condition is satisfiedin the execution period of the PV suppression, that is, in the case inwhich the consumed power Pc′ of the home H occurring when the waterheater 5 performs the water heat-up operation is less than the generatedpower Pa of the power generator 6, the water heater controller 208 maycommand the water heater 5 to perform the water heat-up operation. Inthis case, the water heater controller 208 commands the water heater 5to heat water in the period D3 from the time B to the time E (E′)occurring in the FIG. 8 . This period D3 includes the period ofpurchasing of power from the time B to the time D (D′). Thus this aspectis effective in the case of prioritization of the decreasing of thepower generation loss over the economic effect of power sales.

Further, in the case in which only the first condition is satisfied inthe execution period of the PV suppression, that is, in the case inwhich power from the commercial electrical power system 8 is not beingsupplied to the home H, the water heater controller 208 may command thewater heater 5 to perform the water heat-up operation. In this case, thewater heater controller 208 commands the water heater 5 to heat water inthe period D1 from the time A to the time F occurring in FIG. 8 .Alternatively, the predetermined condition for commanding the waterheater 5 to heat water may be satisfied in the case in which the secondcondition alone is satisfied, the first condition and the thirdcondition are both satisfied, the first condition and the secondcondition are both satisfied, or the second condition and the thirdcondition are both satisfied. In this manner, whatever the type ofcondition that is satisfied, the water heater controller 208 candetermine, variously in accordance with user desires, conditions, or thelike, whether to command the water heater 5 to heat water.

Further, in the aforementioned embodiment, the generated power estimator207 estimates the generated power Pa occurring in the execution periodof the PV suppression as the measurement value of the power Pg suppliedto the home H from the power generator 6 on the day prior to the day ofexecution of the PV suppression. However, the generated power estimator207 may estimate the generated power Pa at the time of the PVsuppression without using the measurement value. For example, thegenerated power estimator 207 can estimate the generated power Paoccurring in the execution period of the PV suppression on the basis ofinformation such as the weather, season, and the like during theexecution period of the PV suppression.

Further, in the aforementioned embodiment, the generated power Paoccurring at the time of day when the PV suppression is executed isestimated by the generated power estimator 207 as the maximum valueamong the measurement values acquired in the previous C days by themeasurement value acquirer 202 at each time included in the specifiedtime slot in which the PV suppression is executed. However, in numerouscases the generated power Pa is actually smaller than the past maximumvalue even when PV suppression is in progress. Thus the generated powerestimator 207 may estimate the generated power Pa to be a value obtainedby correcting the maximum value amount of the measurement valuesacquired in the previous C days. For example, the generated powerestimator 207 may estimate, as the generated power Pa occurring in eachperiod of the day of execution of the PV suppression, a value obtainedby multiplying the maximum value among the measurement values acquiredin the previous C days times a predetermined correction coefficient suchas 0.95, 0.9, or the like.

Further, the power generator 6 is arranged at the home H in theaforementioned embodiment. However, the power generator 6 may bearranged on grounds separated from the home H, and the power may besupplied from a location remote from the home H, as long as the powergenerator 6 is a power system separate from the commercial electricalpower system 8. In this case, the location at which the power generator6 is arranged is included in the meaning of the term “power-consumingarea”. Further, the term “power-consuming area” is not limited to ageneral household as in the aforementioned home H, but may be collectivehousing, a facility, a building, a factory, or the like, as long as thepower-consuming area consumes power from the power generator 6 and thecommercial electrical power system 8.

Further, in the aforementioned embodiment, the power measurement device4 measures the power Pb, Pg, and Pe sent through the power lines D1 toD3, and transmits the measurement values of such power to the controldevice 2. Further, the control device 2 forwards to the PV-PCS 11 of thepower generator 6 the measurement values of the power Pb, Pg, and Peacquired from the power measurement device 4. However, the powermeasurement device 4 may directly transmit to the PV-PCS 11 themeasurement values of the power Pb, Pg, and Pe. Further, a device otherthan the power measurement device 4 may measure the power. For example,the PV-PCS 11 of the power generator 6 may be connected through acommunication line to the CT2 arranged at the power line D2, and thepower Pg output from the power generator 6 may be measured. Further, thehot water supply controller 54 of the water heater 5 may be connectedvia a communication line with the CT3 arranged at the power line D3, andthe power Pe consumed by the water heater 5 may be measured. Measurementin this manner enables appropriate transmission through the wirelessnetwork installed in the home H and enables shared use among the variousapparatuses.

Further, in the aforementioned embodiment, the instruction for PVsuppression distributed from the power server 14 is sent to the controldevice 2 and is forwarded from the control device 2 to the PV-PCS 11.However, the instruction for the PV suppression may be transmitteddirectly to the PV-PCS 11. In this case, by the PV-PCS 11 transmittingto the control device 2 the contents of the instruction for the PVsuppression, the instruction acquirer 201 of the control device 2acquires information such as the schedule, limit value, and the like ofthe PV suppression.

Further, in the aforementioned embodiment, the case is described inwhich the control 2 is arranged in the home H. However, in the presentdisclosure, a device having functions equivalent to the control device 2may be arranged outside the home H. FIG. 16 illustrates an example ofsuch an energy management system 1 a. In the energy management system 1a illustrated in FIG. 16 , the control device 2 is not arranged in thehome H. In place of the control device 2, a router 12 is connected in acommunication-capable manner with each of the operating terminal 3, thepower measurement device 4, the water heater 5, the power generator 6,and the apparatus 7, and the router 12 relays the transmissionsoccurring between each of the apparatuses. Further, the router 12 andthe data server 13 operate together to perform the role of the controldevice 2. Alternatively, the router 12 may be incapable of communicationwith some of the apparatuses within the home H. For example, aconfiguration may be used in which the router 12 and the water heater 5are not connected in a communication-capable manner, and the powergenerator 6 relays communication between the router 12 and the waterheater 5. By omission of the control device 2 in this manner, theconfiguration of the energy management system 1 a can be simplified dueto the ability to reduce the number of the apparatuses arranged in thehome H.

In the aforementioned embodiment, the operating terminal 3 is equippedwith the display and the input device, and the control device 2 acquiresvia wireless or wired communication the input information input to theoperating terminal 3, and transmits display information to the operatingterminal 3. However, in the present disclosure, the control device 2 maybe equipped with the display and the input device. That is to say, thecontrol device 2 may be equipped with the functions of the operatingterminal 3. In this case, the setting information receiver receives thesetting input from the user via the input device with which the controldevice 2 is equipped, and not via the operating terminal 3. Further, thedisplay controller displays the user information via the display withwhich the control device 2 is equipped, and not via the operatingterminal 3.

In the aforementioned embodiment, the controller 21 of the controldevice 2, by the CPU executing programs stored in the ROM or storage 22,performs the functions of each of the terminal communicator 200, theinstruction acquirer 201, the measurement value acquirer 202, the relayunit 203, the determination unit 205, the consumed power calculator 206,the generated power estimator 207, and the water heater controller 208.However, in the present disclosure, the controller 21 may be dedicatedhardware. The term “dedicated hardware” means, for example, a singlecircuit, a composite circuit, a programmed processor, an applicationspecific integrated circuit (ASIC), a field-programmable gate array(FPGA), combinations thereof, or the like. When the controller 21 isdedicated hardware, the functions of each unit may be achieved byseparate respective hardware, or may be achieved collectively by asingle hardware unit.

Further, among each of the functions, a portion may be achieved usingdedicated hardware, and the other portion may be achieved by software orfirmware. In this manner, the controller 21 can achieve theaforementioned various functions by hardware, software, firmware, or acombination of such.

An operating program specifying the operations of the control device 2according to the present disclosure can be used with an existingpersonal computer, information terminal device, or the like, therebyenabling the personal computer, information terminal device, or the liketo function as the control device 2 according to the present disclosure.

Further, any method may be used for distribution of such a program, andfor example, the program may be stored in a computer-readable recordingmedium such as a compact disc read-only memory (CD-ROM), a digitalversatile disc (DVD), a magneto-optical (MO) disc, a memory card, or thelike, and the computer-readable recording medium storing the program maybe distributed through a communication network such as the Internet.

The foregoing describes some example embodiments for explanatorypurposes. Although the foregoing discussion has presented specificembodiments, persons skilled in the art will recognize that changes maybe made in form and detail without departing from the broader spirit andscope of the invention. Accordingly, the specification and drawings areto be regarded in an illustrative rather than a restrictive sense. Thisdetailed description, therefore, is not to be taken in a limiting sense,and the scope of the invention is defined only by the included claims,along with the full range of equivalents to which such claims areentitled.

INDUSTRIAL APPLICABILITY

The present disclosure can be used with advantage for a system and thelike performing control of power.

REFERENCE SIGNS LIST

-   -   1, 1 a Energy management system    -   2 Control device    -   3 Operating terminal    -   4 Power measurement device    -   5 Water heater    -   6 Power generating equipment    -   7, 7-1, 7-2, . . . Equipment unit    -   8 Commercial electrical power system    -   9 Power distribution panel    -   10 PV panel    -   11 PV-PCS    -   12 Router    -   13 Data server    -   14 Power server    -   21 Controller    -   22 Storage    -   23 Timer    -   24 In-home communication device    -   25 Outside-home communication device    -   29 Bus    -   31 PV suppression graphic    -   32 Coordinated control graphic    -   40 Power database    -   50 Heat pump unit    -   51 Tank unit    -   52 Piping    -   53 Hot water storage tank    -   54 Hot water supply controller    -   55 Remote controller    -   56 Mixing valve    -   57 Shower    -   58 Faucet    -   59 Communication line    -   200 Terminal communicator    -   201 Instruction acquirer    -   202 Measurement value acquirer    -   203 Relay unit    -   205 Determination unit    -   206 Consumed power calculator    -   207 Generated power estimator    -   208 Water heater controller    -   210 Instruction storage    -   220 Measurement value storage    -   230 Setting storage    -   D1 to D5 Power line    -   H Home    -   N Wide area network

The invention claimed is:
 1. A control device comprising: an instructionacquirer configured to acquire an instruction to suppress in a specifiedperiod supplying of a generated power generated by a power generatorinstalled in a power-consuming area to a commercial electrical powersystem; a generated power estimator configured to, upon the instructionacquirer acquiring the instruction, estimate the generated power duringa lost power occurring in the specified period, based on a measurementvalue of a power output from the power generator in a period prior tothe specified period; and a water heater controller configured tocommand a water heater installed in the power-consuming area to performa water heat-up operation when a predetermined condition is satisfiedduring the lost power occurring in the specified period, wherein thepower generator comprises a photovoltaic panel and a power conditioningsystem, the lost power (i) occurs due to the power conditioning systemsuppressing the power output from the power generator in the specifiedperiod and (ii) indicates power decrease of total consumed powerrelative to generated power capable of being output and is an amount ofthe power which is not output from the power conditioning system toeither of the commercial electrical power system or the power-consumingarea while the power is being generated by the photovoltaic panel, andthe predetermined condition is satisfied when a consumed power of thepower-consuming area forecast for when the water heater performs thewater heat-up operation is smaller than the generated power estimated bythe generated power estimator.
 2. The control device according to claim1, wherein the predetermined condition is satisfied when the poweroutput from the power generator is larger than a limit value determinedin accordance with the instruction, and the consumed power of thepower-consuming area forecast for when the water heater performs thewater heat-up operation is smaller than the generated power estimated bythe generated power estimator.
 3. The control device according to claim1, wherein the predetermined condition is satisfied when a power is notsupplied from the commercial electrical power system to thepower-consuming area, and the consumed power of the power-consuming areaforecast for when the water heater performs the water heat-up operationis smaller than the generated power estimated by the generated powerestimator.
 4. The control device according to claim 1, wherein thepredetermined condition is satisfied when (i) a power is notsupplied-from the commercial electrical power system to thepower-consuming area, (ii) the power output from the power generator islarger than a limit value determined in accordance with the instruction,and (iii) the consumed power of the power consuming area forecast forwhen the water heater performs the water heat-up operation is smallerthan the generated power estimated by the generated power estimator. 5.The control device according to claim 1, further comprising: a firstmeasurement value acquirer configured to acquire the measurement valueof the power output from the power generator in the period prior to thespecified period, wherein the generated power estimator estimates, basedon the measurement value acquired by the first measurement valueacquirer, the generated power during the lost power occurring in thespecified period.
 6. The control device according to claim 5, whereinthe specified period is a specified time slot occurring on a specifiedday, and the first measurement value acquirer, in a time slot that isthe same time of day as the specified time slot and occurs on a dayprior to the specified day, acquires the measurement value of the poweroutput from the power generator.
 7. The control device according toclaim 6, wherein the first measurement value acquirer, in time slotsthat are the same times of day as the specified time slot and occur on aplurality of days prior to the specified day, acquires measurementvalues of the power output from the power generator, and the generatedpower estimator estimates, as the generated power during the lost poweroccurring in the specified period, a maximum value from among themeasurement values in the plurality of days acquired by the firstmeasurement value acquirer.
 8. The control device according to claim 1,further comprising: a second measurement value acquirer configured toacquire a measurement value of a consumed power of the power-consumingarea occurring prior to the water heater performing the water heat-upoperation, a third measurement value acquirer configured to acquire ameasurement value of a consumed power of the water heater occurringprior to the water heater performing the water heat-up operation, and aconsumed power calculator configured to calculate the consumed power ofthe power-consuming area forecast for when the water heater performs thewater heat-up operation, by (i) subtracting the measurement value of theconsumed power of the water heater acquired by the third measurementvalue acquirer from the measurement value of the consumed power of thepower-consuming area acquired by the second measurement value acquirer,and (ii) adding a rated value of the consumed power of the water heater.9. The control device according to claim 1, wherein, upon theinstruction acquirer acquiring the instruction, the water heatercontroller, in the specified period: (i) commands the water heater toperform the water heat-up operation when a value obtained by adding afirst threshold to the consumed power of the power-consuming areaforecast for when the water heater performs the water heat-up operationis smaller than the generated power estimated by the generated powerestimator, and (ii) commands the water heater to stop the water heat-upoperation when a value obtained by adding a second threshold smallerthan the first threshold to the consumed power of the power-consumingarea forecast for when the water heater performs the water heat-upoperation is larger than the generated power estimated by the generatedpower estimator.